Aspiring

With rain falling on Tuesday and Wednesday up to 1900m saturating the snow pack there will be wet snow hazards at mid and lower elevations. Areas such as the traverse to the Brewster Glacier will be threatened by these type of avalanches. Up to 40cm of snow fell above 1900m accompanied by winds up to gale strength from the NW. Prior to the storm there was already large amounts of loose dry snow available for transport. These factors will have combined to produce a wind slab hazard at higher elevations.

Wet slab and loose wet avalanches have been observed at mid and lower elevations due to the warm wet snowpack conditions. Above 1900m wind slab activity is anticipated to have occurred during the storm. Previously, widespread size 1-2 natural wet avalanches were observed on Monday and Tuesday on steeper solar aspects as the days warmed.

If you see any recent avalanche occurrences or have any relevant snowpack information or photos, you can share them via the Public Observations link on the NZAA home page.

Approximately 15-40cm of new snow fell above 1900m from Tuesday to Thursday. This snow is likely to been re-distributed by strong NNW winds and there is likely to be areas of slab, wind pressed and wind scoured snow. Below 1900m rain has saturated the snow pack with isothermic conditions reported in neighbouring regions.

Previously 20-40 cm of loose dry snow had fallen over last weekend. This snow has generally well bonded to the old snow surface. Before this, on 1st - 4th of August, very strong winds from the west and south have significantly stripped any exposed faces and features and created multiple layers of very dense hard slab ranging from 10-60cm thick. This slab now appears very stubborn and unreactive. Large cornices have also formed above 1800m.

The snowpack remains relatively shallow for the time of year. Approximately 60- 70 cm below 1700m and 120cm at 2000m. Crevasses are still very open, and many rock features are still visible, particularly on west-facing aspects. Although the lower part of the snowpack also appears consolidated and unreactive, the Aspiring region is very large, and there is still limited data.

Caution should still be taken, particularly in steeper, more extreme terrain where unknown weaknesses may exist.

Cloud about the terrain in the morning, otherwise fine.

Wind at 1000 metres: Light.

Wind at 2000 metres: Westerly 30 km/h.

Wind at 3000 metres: Westerly 30 km/h, rising to 60 km/h for a time in the evening.

Freezing level: 1800 metres.

Exposed areas such as ridgelines may have been stripped back to old ice layers by strong winds. Rain has fallen to 1800m creating a frozen snow surface this morning which will present a sliding hazard till the day warms. Depending on your objective, an ice axe and crampons could be necessary.

Moderate

• The snowpack structure is well understood.
• We are uncertain due to a limited number of field observations.
• We are uncertain due to the variability of wind effect on the snowpack.